Camping is an extremely popular activity and being able to take one's living quarters with one's vehicle allows many who would prefer not to stray from the road to still enjoy being in the outdoors. Although dedicated recreational vehicles (RV's) are in widespread use, they are expensive, take up valuable space when not in use, and may have limited off-road/rough road capability. Towed trailers are also common but, like RV's, take up valuable space when not in use, and may have limited off-road/rough road capability.
Camper tops or shells that fit onto the back of pickup trucks are less expensive than dedicated RV's or camper trailers, make use of existing vehicles, and make it easier to travel in areas that RV's and trailers may be unable to negotiate. Thus, integrating the living quarters with the vehicle enhances the convenience of camping.
There are numerous types of camper shells. Many simply attach to the top perimeter of the pickup truck bed. There is generally some inside space over the roof of the truck cab with only a little head-room that is adequate for sleeping but nothing else. For added head-room above the main area in the truck bed, some shells have tops that can be raised. Nonetheless, space is always limited.